4. Discussion
In our study, two previously overlooked yet critical threats to cat
survival were identified in the Gyatong Grassland: killing by
free-ranging dogs and genetic contamination from domestic cats, which
supplements our previous understanding of the major threats of pika
poisoning programmes and illegal hunting (Sanderson et al. ,
2010).
4.1 Killing by free-ranging
dogs
We understand that solely based on the results from interviews and
camera trap monitoring, we cannot prove that free-ranging dogs killed
both cats – after all, the scene of killing was neither recorded nor
seen by anyone. However, combined with other evidence from previous
research as well as our observations of dogs’ predation on other
sympatric wildlife in the region, we do believe that free-ranging dogs
have been the killers.
Liu’s study (2020) in the Sanjiangyuan Region revealed that stray dogs
showed fairly large home ranges (10 km2 on average),
large body weight (over 20 kg), and a high hunting success rate brought
by group-hunting strategies, which indicated that they might be in a
dominant position in their relationships with sympatric meso-carnivores.
Meanwhile, stray dogs are notoriously known to harass sympatric wildlife
and finally resulting in an reduction of survival rate via direct
killing or increased stress level, altered activity pattern and habitat
use (Lenth, Knight, & Brennan, 2008; Gingold et al. , 2009; Younget al. , 2011; Hughes & Macdonald 2013). For example, in New
Zealand just one stray dog killed about 500 kiwis (Apteryx
australis ) in six weeks, accounting for more than half of local kiwi
population (Taborsky, 1988). This is particularly worrying in the
context of the recent surge in stray dog population in the Tibetan
region. The collapse of the Tibetan mastiff market along with the
implementation of nomadic settlement projects has resulted in a dramatic
decrease in the economic and productive value of domestic dogs, leading
to widespread dog abandonment in the region (Jenny, 2012). Official
statistics from 2016 show that there were more than fifty thousand dogs
in Golog Prefecture alone, Qinghai province, of which fourteen thousand
were stray dogs (Yin et al. , 2017). The spots of these dogs’
predation on wildlife have been frequently made (Fig. 4a, b; Yanget al. , 2019). Besides the fairly high population density (4.6
individual / km2 near villages), the growth rate of
them (10.3% on average) also indicates that this issue requires more
attention and efforts (Liu, 2020).
In the case of Gyatong, our interviews revealed a fact that the current
rearing methods of locals blurred the boundary between domestic dogs and
stray dogs. At night or during the absence of owners, these domestic
dogs would be unchained and allowed to hunt for themselves
(Messerschmidt, 1983; Cui, 2006). As a natural result, such potential
overlap in both time and space between free-ranging dogs and nocturnal
Chinese mountain cats (Liao, 1988) has facilitated interactions
detrimental to the cat. Moreover, cats are not the only victims in the
region, with other meso-carnivores (e.g., Asian badgers Meles
leucurus , Tibetan foxes) all threatened by these dogs. In June 2019,
during the absence of the owner of a house 150 m away from the den of
the Chinese mountain cat family, his two dogs were found to kill at
least two Tibetan foxes, one steppe polecat (Mustela eversmanii ),
four Asian badgers, and one Himalayan marmot (Marmota himalayana )
(Fig. 4b, Fig. 6; all these carcasses were found near the house and
probably there were more undiscovered). Badgers and marmots were all
consumed by dogs, but carnivores such as foxes and polecats were only
killed and left intact, in accordance with previous diet analyses (Liu,
2020). Consequently, this leads to an increased exposure of the cats to
free ranging dogs, because when dogs are attracted to the dens of
badgers and marmots, the cats might be using them as hiding burrows
(Sanderson et al. , 2010; Han et al. , 2020; Fig. 4c).
4.2 Genetic contamination by domestic
cats
Compared with threats from free-ranging dogs, genetic contamination from
domestic cats revealed by our genetic analysis is a much more
imperceptible threat, but with a long-lasting impact on the survival of
the cat as a unique lineage.
Despite the maintenance of typical morphological (Fig. 1a) and
ecological features, our two Chinese mountain cat
specimens
carried both mitochondrial and nuclear genotype of domestic cats. This
is the first time that wild individuals of the Chinese mountain cat were
proven to contain the DNA of their domestic relatives. On the flip side,
genetic introgression from the Chinese mountain cat to sympatric
domestic cats has been proven with genetic evidence and supported by
local observations. Yu et al. (2021) found that domestic cats
sampled from the core range of the Chinese mountain cat’s distribution
(i.e., eastern Qinghai and northwestern Sichuan) carried 5-10% genetic
admixture from Chinese mountain cats, which dated back to around 7.4
generations ago (approximately 20 years). Comparatively, our case
samples from two hybrid cubs showed approximately 30% genetic source
from Chinese mountain cat, suggesting a more recent admixture event or
higher local introgression background. The hybrids also displayed
intermediate morphological characters, e.g., light brown fur, little ear
tufts, light brown pupils (Fig. 5b). Our finding supported that
long-term bidirectional gene introgression between Chinese mountain cats
and local domestic cats existed in the Gyatong Grassland and adjacent
regions.
Moreover, local herdsmen claimed that the cats were rather common around
their village about ten years ago, the time when many domestic cats were
kept as pets. During mating seasons in spring, they could hear the cat
screaming for the whole night, and a few locals have even seen male
Chinese mountain cats wandering into their village to fight male
domestic cats and mate with females (the opposite was not learned during
this survey). Such potential asymmetric hybridization is probably
related to the larger body size of the Chinese mountain cats compared to
domestic cats, which gives them a mating advantage in accessing females
(Similar phenomena of male Chinese mountain cats mating with the smaller
female Asiatic wildcats F. s. ornate have also been reported; Yuet al. , 2021). Furthermore, from camera trap monitoring, we know
that the male kitten has survived. On March 2019, he was found urine
marking a boulder located below the third den of the breeding family,
right after a white domestic cat did so, which suggested the opportunity
for their mating competition.
The bidirectional gene flow
between the Chinese mountain cat and local domestic cats in the
Sanjiangyuan Region, if confirmed by future genetic analysis on larger
scale, could be quite detrimental to the vulnerable Chinese mountain cat
species, jeopardizing its distinctiveness, genetic integrity, and even
its survival in the alpine
environment.
Extensive
studies have demonstrated a similar genetic contamination crisis faced
by the European wildcat (F. s. silvestris ), which commonly
interbreeds with the ubiquitous feral cats,
raising
widespread
conservation
attention (Allendorf et al. , 2001; Oliveira et al. , 2008).
For Chinese mountain cats, more research efforts are in urgent need to
investigate the extent of the problem.
4.3 Tricky balance among humans, dogs, cats and beyond
Both cats were genetically contaminated by domestic cats and very
likely, killed by free-ranging dogs, which are almost inevitable results
from their proximity to human settlements (Webb et al. , 2016).
Among all the three dens of the family, the last one was located less
than 100 meters away from a herdsman’s house who owns one cat and three
dogs. Such proximity facilitates frequent contact of the Chinese
mountain cats with free-ranging dogs and domestic cats. Apparently,
there requires no further words to explain the legitimacy of all of
their existences. However, this fact indeed constitutes the very bedrock
when we are trying to find a way out of this dilemma.
The complexity of the issue is rooted in both the material as well as
the spiritual life of the Tibetans. On the one hand, domestic dogs and
associate rearing methods are of utter importance to the safety of
property and life of local herdsmen. Currently, in the Sanjiangyuan
Region and most areas on the Tibetan Plateau, wolves and bears are two
carnivores that have caused most human-wildlife conflicts (Dai et
al. , 2020). As the major ‘weapon’ against them, unchained dogs,
particularly Tibetan mastiffs, are of unparalleled importance to local
herdsmen (Messerschmidt, 1983). On the other hand, the locals seem to
acquiesce in the killing behaviors of their dogs. Our interview
suggested that many of the locals were unaware of the dog’s negative
impact on wildlife. Despite so, from the fact that most local herdsmen
would set their dogs free when they are leaving, it is clear that they
are allowing dogs to prey on wildlife. In this case, the real causes of
such avoidable incidents were selectively attributed to the poor and
inevitable fates of the victim animals, instead of the indifference (or
‘bad karma’ if more precisely) of the dog owners (note that by no means
we are criticizing Tibetan Buddhism here because it was the exact reason
that has kept the Tibetan Plateau one of the most pristine habitats to
wildlife in the world, as shown in Ma & Chen, 2005; Shen et al. ,
2012; Li et al. , 2014).
Therefore, it was not realistic to simply ask nomads to chain their
domestic dogs all the time. Leaving dogs to neighbors seems worth trying
if the causal connections could be established between ‘setting dog
free’ and ‘deaths of innocent wild animals’, yet which might be most
effectively done by someone with same religion. Comparatively, for stray
dogs, potential management measures seem less tricky and more feasible.
According to the interview conducted in Gyatong, most local herdsmen did
not mind the treatments of stray dogs (e.g., neutering, killing) as long
as they are not treated on-site (“you can put them in a truck and take
them away, but do not tell me what you will do to them”). The only
difficult part of this solution is that surrounding Tibetan monasteries
must be well informed and educated, since during our survey they were
found feeding and harboring stray dogs to a great extent (for example, a
Nunnery in the study area have been keeping over one hundred stray dogs
and none of them was chained).
Consequently, it now seems to us the most feasible solutions to mitigate
the situation in Gyatong are, (1) carefully monitoring and regularly
catching stray dogs in the region, (2) persuading dog owners send their
dogs to a host family instead of setting them free when they are away,
(3) establishing the causal link between ‘dead wild animals’ and ‘dogs
owners’ misdeeds’ in the mindsets of the locals. For dog-release at
night, it seems to us there is no feasible alternative for now, unless
the current conflicts between humans, bears and wolves are alleviated.
However, as stated above, suggestions as such might also be applicable
to the region alone, considering the very high yet often overlooked
cultural biodiversity within the Tibetan Plateau (e.g., studies
conducted in the Golog Prefecture suggested that the locals show no
tolerance to any dog-hurting behavior; Liu, 2020).
To summarize, through the examination and analysis on two carcasses from
a consistently monitored Chinese mountain cat family and two hybrids, as
well as the survey on free-ranging dogs in this area, we suggest that
two so-far overlooked threats to the cat are elicited from domestic dogs
and cats, their foes and their kins, in addition to the
previously-identified threats of pika poisoning programs and illegal
hunting. With the synthesis on available knowledge and observations, the
complexity of the issue was illustrated and accordingly, potential
solutions were proposed. With the species up-listed to the National
First-Class Protected Wild Animal, more attention should be paid to the
Chinese mountain cat. Along with it, we hope more research and
conservation resources and efforts will be directed to this endemic
carnivore.